1. Field of the Invention
The present invention generally relates to a mobile communication system using Mobile Internet Protocol (IP), and in particular, to a method for performing HandOff (HO) using Proxy Mobile IP (PMIP) to reduce the handoff latency of a Mobile Station (MS) during the HO.
2. Description of the Related Art
The development of mobile communication networks and the growth of Wireless Local Area Network (WLAN)-based services are a driving force behind the increase in number of users that communicate wirelessly using their Mobile Stations (MSs). In this context, more attention is attracted to services through MSs. Mobile IP has been developed to manage the locations of MSs and enable seamless communications for the MSs during HO. There are two Mobile IP versions, Mobile IPv4 (MIPv4) and MIPv6. Mobile IP advantageously allows MSs to transmit and receive data seamlessly, still maintaining the same IP address.
However, Mobile IP itself creates too much overhead to be used in cellular mobile communication networks such as 3rd Generation Partnership Project 2 (3GPP2). To reduce the overhead, PMIP has emerged. PMIP reduces HO latency relative to Mobile IP. Yet, MSs have to operate independently of a PMIP network environment irrespective of whether the PMIP network environment supports the conventional IP technology, i.e. Simple IP, MIPv4, or MIPv6.
Efforts are taking place to improve performance by PMIP in mobile communication systems. Especially PMIP is under standardization in the 3GPP2 to improve HO performance. Accordingly, there exists a need for a HO procedure for efficiently supporting MSs using a MIPv4 protocol stack and a method for efficiently managing the structure of HO data in a mobile communication system using MIPv4. There also exists a need for a HO procedure for efficiently supporting MSs using a MIPv6 protocol stack and a method for efficiently managing the structure of HO data in a mobile communication system using MIPv6.